1. Field of the Disclosure
This disclosure relates in general to Polycrystalline Diamond Compact drill bits, and in particular, to a method of and an apparatus for PDC bits with integrated sensors and methods for making such PDC bits.
2. The Related Art
Rotary drill bits are commonly used for drilling boreholes, or well bores, in earth formations. Rotary drill bits include two primary configurations and combinations thereof. One configuration is the roller cone bit, which typically includes three roller cones mounted on support legs that extend from a bit body. Each roller cone is configured to spin or rotate on a support leg. Teeth are provided on the outer surfaces of each roller cone for cutting rock and other earth formations.
A second primary configuration of a rotary drill bit is the fixed-cutter bit (often referred to as a “drag” bit), which conventionally includes a plurality of cutting elements secured to a face region of a bit body. Generally, the cutting elements of a fixed-cutter type drill bit have either a disk shape or a substantially cylindrical shape. A hard, superabrasive material, such as mutually bonded particles of polycrystalline diamond, may be provided on a substantially circular end surface of each cutting element to provide a cutting surface. Such cutting elements are often referred to as “polycrystalline diamond compact” (PDC) cutters. The cutting elements may be fabricated separately from the bit body and are secured within pockets formed in the outer surface of the bit body. A bonding material such as an adhesive or a braze alloy may be used to secure the cutting elements to the bit body. The fixed-cutter drill bit may be placed in a borehole such that the cutting elements abut against the earth formation to be drilled. As the drill bit is rotated, the cutting elements engage and shear away the surface of the underlying formation.
During drilling operations, it is common practice to use measurement while drilling (MWD) and logging while drilling (LWD) sensors to make measurements of drilling conditions or of formation and/or fluid properties and control the drilling operations using the MWD/LWD measurements. The tools are either housed in a bottom-hole assembly (BHA) or formed so as to be compatible with the drill stem. It is desirable to obtain information from the formation as close to the tip of the drill bit as is feasible.
The present disclosure is directed toward a drill bit having PDC cutting elements including integrated circuits configured to measure drilling conditions, properties of fluids in the borehole, properties of earth formations, and/or properties of fluids in earth formations. By having sensors on the drill bit, the time lag between the bit penetrating the formation and the time the MWD/LWD tool senses formation property or drilling condition is substantially eliminated. In addition, by having sensors at the drill bit, unsafe drilling conditions are more likely to be detected in time to take remedial action. In addition, pristine formation properties can be measured without any contamination or with reduced contamination from drilling fluids. For example, mud cake on the borehole wall prevents and/or distorts rock property measurements such as resistivity, nuclear, and acoustic measurements. Drilling fluid invasion into the formation contaminates the native fluid and gives erroneous results.